1. Field of the Invention
The present invention relates to a method, apparatus and product for RFID authentication having efficient proactive information security within computational security.
2. Prior Art
An RFID tag is a small microchip, supplemented with an antenna that transmits a unique identifier in response to a query by a reading device. RFID technology is designed for the unique identification of different kinds of objects. According to [14] RFID communication systems are composed of three major elements: (i). a RFID tag carries object identifying data; (ii). a RFID reader interfaces with tags to read or write tag data; (iii). a back-end database aggregates and utilizes tag data collected by readers. The RFID sender (or reader) broadcasts an RF signal to access data stored on tags that usually includes a unique identification number. RFID tags are designed as low cost devices that use cheap radio transmission media. Such tags have no or very limited internal source of power; nevertheless, they receive their power from the reading devices. The range of the basic tags transmission is up to several meters. Possible applications of the RFID devices include: RFID-enabled banknotes, libraries, passports, pharmaceutical distribution of drugs, and organization of an automobile security system or any key-less entry system. Nevertheless, the wide deployment of RFID tags may cause new security and privacy protecting issues.
RFID tags usually operate in insecure environment. The RFID reader privacy may be compromised by an adversary that extracts unencrypted data from the unprotected tags. RFID tags are limited devices that cannot support complicated cryptographic functions. Hence, there is nowadays an interest in achieving high security and privacy level for the RFID devices, without usage of computationally expensive encryption techniques.
A brief introduction to RFID technology appears in [14] where potential security and privacy risks are described. Schemes for providing desired security properties in the unique setting of low-cost RFID devices are discussed in [14]. The authors of [14] depict several advantages of the RFID tags over traditional optical bar codes. Unlike the optical bar codes, RFID tags are able to read data automatically through non-conducting material at a rate of several hundred tags per second and to a distance of several meters up to hundred meters. The authors state that low-cost smart RFID tags may become an efficient replacement for optical bar codes. The main security risks stated are the violations of “location privacy” and denial of service that disable the tags. With the RFID resource constraints in mind, the cryptography techniques proposed in developing the RFID security mechanisms are: (i) a simple access mechanism based on hardware-efficient one-way hash functions, low-cost traditional symmetric encryption schemes, randomizing tag responses based on random number generator; (ii). integrating RFID systems with a key management infrastructure. Regardless of the mechanisms used for privacy and access control, management of tag keys is an important issue. The new challenge in the RFID system design is to provide access control and key management tools compatible with the tags cost constraints.
A research survey in [10] examines different proposed approaches for providing privacy protection and integrity assurance in RFID systems. In order to define the notions of “secure” and “private” for RFID tags a formal model that characterizes the capabilities of potential adversaries is proposed. The author states that it is important to adapt RFID security models to cope with the weakness of the RFID devices. Few weak security models that reflect real threats and tag capabilities are discussed. A “minimalist” security model that serves low-cost tags is introduced in [11]. The basic model assumption is that the potential RFID adversary is weaker than the one in traditional cryptography. Besides, such an adversary comes into scanning range of a tag only periodically. The minimalist model aims to take into account the RFID adversary characteristics. Therefore, this model is not perfect, but it eliminates some of the standard cryptographic assumptions that may be not appropriate for the deployment in other security systems that are based on a more powerful adversary model. The author of [11] states that standard cryptographic functionality is not needed to achieve necessary security in RFID tags.
An adversary model adapted to RFID protocols is introduced in [1]. Many existing privacy protecting RFID protocols are examined for their traceability. Traceability is defined as the capability of the adversary to recognize a tag which the adversary has already seen, at another time or in another location [1]. The traceability is stated as a serious problem related to the privacy protection in the RFID systems. The paper concludes that in a realistic model, many protocols are not resistant to traceability.
The Newsletter of the RFID Society [8] proposes zero-knowledge proofs technology in solving the privacy issue for RFID. The main idea is to enhance RFID chips with additional cryptographic functions supporting zero knowledge identity proofs. This approach requires a large amount of memory and long computational time. Basic RFID tags are low-memory devices and are not capable to store and process large amount of data.
Other existing techniques and secure protocols proposed for implementation in existing RFID systems include an inexpensive RFID tag known as Electronic Product Code (EPC) tag, which was developed to protect against RFID tag cloning [9]. Although basic EPC tags possess features geared toward privacy protection and access control mechanisms, notwithstanding they do not possess explicit authentication functionality. That is, EPC standards prescribe no mechanism for RFID-EPC readers to authenticate the validity of the tags they scan, The authors show how to construct tag-to-reader and reader-to-tag authentication protocols.
However, the security analysis of the basic Digital Signature Transponder (DST) RFID tags is described in [3]. The authors also present in detail the successful strategy for defeating the security of an RFID device known as DST. The main conclusion of [3] is that basic DST tags are no longer secure due to the tags weakness caused by the inadequate short key length of 40 bits. Although it is possible to increase the computational security level by increasing the length of the key, still the resulting scheme will not be information secure but only computationally secure.